Dynamic Behavior on Emergency Landing of Light Aircraft with Occupant Restraint System

2012 ◽  
Vol 591-593 ◽  
pp. 2513-2517
Author(s):  
Lin Yin Luo ◽  
Yan Bin He ◽  
Xuan Liu ◽  
Xiao Hu Yao

In the case of aircraft emergency landing, occupants’ safety analysis and research is one of the indispensable links in the verification of airworthiness safety. However, traditional experimental methods is time-consuming, complex and costly, seriously affect the development of new models to market. This paper established a finite element model of the full-size aircraft cockpit according to a certain type of amphibious light aircraft, and adding the dummy and safety belt occupant restraint system finite element model on this basis. In accordance with the requirements of CCAR-23 test conditions, using large dynamic finite element analysis software LS-DYNA numerical simulation was processed to study this aircraft’s emergency landing procedure. This paper investigated the dynamic response of the dummy and head injury criterion (HIC) value etc. The results provide certain reference for aircraft emergency landing safety design.

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Fan Ruoxun ◽  
Liu Jie ◽  
Liu Jun ◽  
Wang Weijun

Occurring resonance may negatively affect the health of the human lumbar spine. Hence, vibration generated in working and living environments should be optimized to avoid resonance when identifying the natural frequency of the human lumbar spine. The range of the natural frequency of the human lumbar spine has been investigated, but its specific numerical value has not been determined yet. This study aimed at presenting an approach based on resonance for predicting the specific numerical value of the natural frequency of the human lumbar spine. The changes in the numerical fluctuation amplitudes and the cycles of lumbar mechanical parameters during resonance are greater than those during nonresonant vibration. Given that the range of the natural frequency has been identified, vibrations at different excitation frequencies within this range can be applied in a human lumbar finite element model for dynamic finite element analysis. When the excitation frequency is close to the natural frequency, resonance occurs, causing great changes in the numerical fluctuation amplitudes and the cycles of lumbar mechanical parameters. Therefore, the natural frequency of the lumbar finite element model could be back-calculated. Results showed that the natural frequency of the established model was 3.5 Hz. Meanwhile, the closer the excitation frequency was to the natural frequency, the greater the changes in the numerical fluctuation amplitudes and cycles in the parameters would be. This study presented an approach for predicting the specific numerical value of the natural frequency of the human lumbar spine. Identifying the natural frequency assists in finding preventive measures for lumbar injury caused by vibration and in designing the vibration source in working and living environments to avoid approximating to the natural frequency of the human lumbar spine.


2014 ◽  
Vol 638-640 ◽  
pp. 605-608
Author(s):  
Zhong Xiao ◽  
Yuan Zhan Wang

The calculation for the gravitational settling and position of a sunken ship can provide important information for a reasonable salvage program. A 3D elastic-plastic dynamic finite element model was established to calculate the gravitational settling of a sunken ship in soft foundation of Tianjin port in China. The results showed that a large amplitude settlement had happened in previous seconds, and then settlement tended to be stable. The stable value was in keeping with the field observation value. Besides, a collapse pit on the top surface of soils under the hull induced by the gravity of dredge was formed while soils around the compression region were raised. Moreover, the strain value increased rapidly in previous seconds which induced a large amplitude settlement of the ship and then tended to be stable.


1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.


Author(s):  
Luiz T. Souza ◽  
David W. Murray

The paper presents results for finite element analysis of full-sized girth-welded specimens of line pipe and compares these results with the behavior exhibited by test specimens subjected to constant axial force, internal pressure and monotonically increasing curvatures. Recommendations for the ‘best’ type of analytical finite element model are given. Comparisons between the behavior predicted analytically and the observed behavior of the experimental test specimens are made. The mechanism of wrinkling is explained and the evolution of the deformed configurations for different wrinkling modes is examined. It is concluded that the analytical tools now available are sufficiently reliable to predict the behavior of pipe in a manner that was not previously possible and that this should create a new era for the design and assessment of pipelines if the technology is properly exploited by industry.


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